Year	Percent
1967	0.52125
1968	4.43689
1969	4.21712
1970	10.51274
1971	0.91718
1972	16.12928
1973	-7.01719
1974	-5.73118
1975	-1.71718
1976	-7.93591
1977	-3.78916
1978	-1.24632
1979	-2.31383
1980	-7.03732
1981	1.02633
1982	0.34577
1983	0.19067
1984	-3.04679
1985	-4.17585
1986	0.88685
1987	7.05442
1988	3.35507
1989	6.54185
1990	3.49037
1991	4.00393
1992	1.05925
1993	8.38746
1994	0.40439
1995	1.36612
1996	-1.071
1997	-2.08953
1998	-3.25235
1999	0.14587
2000	0.04407
2001	0.58221
2002	1.2997
2003	3.01413
2004	0.71974
2005	0.30946
2006	2.31736
2007	0.87689
2008	-1.33272
2009	-4.81279
2010	-1.92546
2011	1.28984
2012	-1.02619
2013	0.11762
2014	0.32114
2015	0.54672
2016	1.04207
2017	0.17055